1. Field of the Invention
The present invention relates to a semiconductor memory device.
2. Related Art
FeRAMs (Ferro-electric Random Access Memories) utilizing ferroelectric capacitors have attracted attention as one of non-volatile semiconductor memories. Recently, reduction in chip size has been demanded in the ferroelectric random access memories to reduce manufacturing costs. To reduce the chip size, it is effective to reduce a unit cell size.
For example, when a contact is provided between two adjacent ferroelectric capacitors, a distance between the two ferroelectric capacitors must be set to be large to a certain extent to prevent a short circuit between the ferroelectric capacitor and the contact. Meanwhile, when the area of the ferroelectric capacitor is reduced, a signal difference (a read voltage difference between data “1” and data “0”) may be reduced.